Thanks for the info on overclocking, will get to that soon, just finishing up my temp experiments now.
At stock speed the AM-V2 hashes at between 616 and 624 GHs. Top on, top off makes absolutely no difference in hash rate over longer periods.
The machine's top two blades do run 2 C cooler with top plate in place.

While I'm here... just ordered a second AM-V2 anyone have any thoughts on stacking vs not stacking and also opinions on PSU, I have  a 1300 watt Platinum PSU from EVGA that looks like it could run two of these but BTC Gardens' stated specs call for a 750 W PSU for each.
(When I first plugged my V2 in I checked and it was drawing 634 W at the wall but I haven't checked to see how much this fluctuates while mining).